The background of a first group of embodiments of the invention will be explained below.
There has been already the machine tool disclosed in Japanese Patent Official Gazette No. 2968938. The machine tool is provided with a pair of right and left comparatively large side plane walls which are forwardly extended at right and left end parts of the front face of a machine bed (a base). A jig for supporting a work is provided between the side plane walls. The front lower part of the machine bed is forwardly extended to below the jig, and a chip discharging means is formed on the top face of the front lower part.
The background of second and third groups of embodiments of the invention will be explained.
The machine tool disclosed in Japanese Patent Official Gazette No. 2968938 has the following configuration in addition to the above-mentioned structure. That is, a machining head is forwardly extended from the top of the base to be arranged right above the jig.
A machine tool shown in FIG. 40 has been conventionally used. The front lower part of a base 100 is forwardly extended to reach below a jig 28 for supporting a work ‘w’. A machining head 102 is forwardly extended from the top of the base 100 to be located right above the jig 28. In addition, a chip discharging means is formed on the top face of the front lower part of the base 100. Such a configuration is in accordance with the machine tool disclosed in Japanese Patent Official Gazette No. 2968938.